AstronomyDetermination of time, longitude, latitude, and azimuth . DETERMINATION OF AZIMUTH. 141 ings upon the mark, and corresponding readings of the striding level will be unnecessary. Inchoosing the position of the mark it should be kept in mind that the higher the line of sight to itabove the intervening ground the more steady the light may be expected to show and the smallerthe errors to be expected from lateral refraction. SHELTER FOR THE INSTRUMENT. An especially designed tent should be used to shield the instrument from the wind. Illus-trations 16 and 17 show two tents which have prove
AstronomyDetermination of time, longitude, latitude, and azimuth . DETERMINATION OF AZIMUTH. 141 ings upon the mark, and corresponding readings of the striding level will be unnecessary. Inchoosing the position of the mark it should be kept in mind that the higher the line of sight to itabove the intervening ground the more steady the light may be expected to show and the smallerthe errors to be expected from lateral refraction. SHELTER FOR THE INSTRUMENT. An especially designed tent should be used to shield the instrument from the wind. Illus-trations 16 and 17 show two tents which have proved satisfactory. The tent should be only asheavy as is necessary to withstand strong winds and protect the instruments from rain. Whennot in actual use the instruments used for azimuth observations should be dismounted and placedin their packing cases. Owing to the short time during which an azimuth station is occupiedfor observations it is usually not necessary or desirable to erect a wooden observatory to protect the instruments. ARTIFICIAL HORIZON. Instead of
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Keywords: ., bookauthoruscoasta, bookcentury1900, bookdecade1910, bookyear1913
